X axis squished

[Helen Kamens-Horton]

I'm relatively new to ggplot2.  I'm trying to make a bar graph, but my x axis gets squashed.  The resulting graph is attached as a pdf.  Any idea on how I can get rid of the extra white space on the right side of the graph?

LOCO_BT <- read.csv ("ForGraphs.csv", header = TRUE)

### GET SUMMARY STATISTICS TO MAKE GRAPHS

LOCO <- summarySE(LOCO_BT, measurevar="Diff_BC", groupvars=c("Genotype","DUM_Dose"), na.rm = TRUE)

LOCO

### CREATE A SHORT CUT TO MAKE BLACK/WHITE GRAPHS

BW_Graphs <- theme_bw()+

  theme(

    plot.background = element_blank(),

    panel.grid.major = element_blank(),

    panel.grid.minor = element_blank(),

    panel.border = element_blank()) +

  theme(axis.line = element_line(color = 'black'))

### GRAPH WITH MEAN +/- SEM 

ggplot(LOCO, aes(x=DUM_Dose, y=Diff_BC, fill=(factor(C57_LOCO$Genotype, levels=c("WT", "HET", "KO"))))) + 

  geom_bar(position=position_dodge(.9), 

           stat="identity",

           colour="black", # Use black outlines,

           size=.3) +

  scale_fill_manual(breaks=c("WT", "HET", "KO"),

                    values=c("white", "gray", "black"),

                    name="Genotype") +

  geom_errorbar(aes(ymin=Diff_BC-se, ymax=Diff_BC+se), # Need to change for future graphs to variable of interest eg Diff_BC

                size=.3,        #Thinner lines

                width=.2,       # Width of the error bars

                position=position_dodge(.9)) +

  xlab("Dose") +

  ylab("Beam Crosses") +

  ggtitle("Activity") +

  scale_y_continuous (limits=c(-125, 25), expand = c(0, 0)) +

  scale_x_discrete(breaks=c("1", "2", "3"), labels=c("0.25", "0.5", "1.0"))+

  BW_Graphs

Here is an example of what I get from my summarySE

Genotype DUM_Dose  N     Diff_BC       sd        se       ci

1      HET        1 16  -20.250000 48.78046 12.195115 25.99327

2      HET        2 15  -69.133333 43.72947 11.290901 24.21657

[Helen Kamens]

In case anyone else has this problem this small change in the code fixed it:

scale_x_discrete(breaks=c("1", "2", "3"), labels=c("0.25", "0.5", "1.0"), limits=c(1,2,3))

Just to be clear there should have only been 3 categories on the X-axis.  The problem I was have made it seems like there should have been a 4th category that wasn't appearing.